Aircraft power plant apparatus



Nav. 15, 1949 A l. WHITEMAN ETAL. 2,487,842

AIRCRAFT POWER PLANT APPARATUS Filed March 9, 1948 IN EN 0R5. IrazzCDauenpozf ATTORNEY Patented Nov. 15,1949

AIRCRAFT rowan PLANT APPARATUS Irvin Whiteman, Philadelphia, Pa., andCharles C. Davenport, Los Angeles, Cali f., assignors to WestinghouseElectric Corporation, East Pittsburgh, Pa a corporation of PennsylvaniaApplication March 9, 1948, Serial No. 13,828

9 Claims. (Cl. 230--207) This invention relates to power plants, moreparticularly to lubrication systems therefor, and has for an objecttoprovide improved apparatus of this character. I

Another object of the invention is to provide novel apparatus .formaintaining the lubricant of a power plant at suitable temperatures.

In aircraft pbwered by gas turbine plants where combustion air isreceived through a forwardlydirected inlet, the ram pressure on theentering air at high flight speeds may be so great as to raise thetemperature of the entering air to a degree rendering it unsuitable foruse as a cooling medium for lubricant in the power plant lubricationsystem. Consequently, if a portion of this air is to be utilized as amedium for absorbing heat from the power plant lubricant, it must becooled to provide the necessary temperature differential relative to thelubricant.

To this end, the present invention provides an air-lubricant cooler inthe lubrication system of an aircraft power plant, together with aconduit for passage of compressed air from the plant to the cooler. Thenecessary reduction in cooling air temperature is effected by either aheat exchanger cooled by inlet air, or by expansion of the compressedair through an expansion device, such as an air turbine, or by acombination of the two.

, Therefore, a further object of the present inven- 2 pressed in thecompressor, the compressed air is then heated in the heating apparatusby combustion of fuel, supported by the compressed air. The resultingmotive fluid, comprising the products of combustion and the excesscompressed air, drives the turbine and is then discharged through thepropulsion nozzle as a jet, the reaction of which serves to propel theaircraft. The turbine extracts at least suflicient power from the motivefluid to drive the compressor and auxiliaries. The fuel is supplied tothe air heating apparatus, under the control of a throttle valve, bysuitable means, for example, a positive displacement pump which ispreferably driven by the turbine.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawings, forming a part of this application, inwhich the single figure is a longitudinal sectional view of apparatusembodying the present invention.

The power plant shown in the figure comprises,

'in general, an outer casing structure l0, open tion is to .providemeans for reducing the temperature of airto a degree rendering itsuitable for use as a cooling medium for an air-lubricant cooler.

Another object of the invention is to provide an air-cooling systemwherein the air to be cooled is caused to perform work by motivating anair turbine, thereby losing heat.

While air cooling means of the character hereinafter disclosed will befound useful in many situations and types of apparatus, they areparticularly usefuLin gas turbine power plants for aircraft propulsion.

A typical power plant of the type referred to is disclosed in U. S.Letters Patent No. 2,405,723, granted August 13, 1946 to the assignee ofthe present application, wherein there is described a gas turbine powerplant for propulsion of aircraft, and includes an air compressor, airheating apparatus, a turbine, and a propulsion jet nozzle all housedwithin a streamlined tubular casing. A plant of this character isparticularly suitable for propelling aircraft at high speeds from end toend, and having a central core structure ll providing an annular flowpassage l2, which extends fore and aft with respect to the aircraft inwhich it is mounted. The central core structure II is supported by thecasing structure along its longitudinal axis and includes a hollowfairing cone ll defining with the forward or left end of the casing In,as viewed in the figure, the inlet portion of the flow passage l2. Thefairing cone mayhouse a fuel pump (not shown), and other auxiliaryvapparatus, and is supported from the casing by hollow compressor guidevanes IS. The core structure also includes the rotor ll of an axial-flowcompressor l8, the rotor IQ of a turbine 2|, and a conical tailpiece 22which defines, with the rear end of the casing structure, a propulsionnozzle 23. The intermediate portion of the core structure between thecompressor and the turbine comprises an inner wall structure 24, whichhouses a shaft 25 connecting the turbine rotor l9 and compressor rotorl1, and defines with the casing iii an annular combustion chamber 26.The shaft 25 is journaled in suitable bearings 21, 28 and 29. I

The combustion chamber 26 is provided with a suitable burner or burners,such as shown in the copending application of Way et al., Serial No.511,468, filed November 23, .1943, for heating the air compressed by thecompressor. In the embodiment shown herein, aperforated, tapered, doubleannular burner ii is mounted in the an- A the burner tube 3|.

nular combustion chamber 28 with its large open end 32 directeddownstream. Fuel under pressure is supplied to the burner from a fuelsupply through atomizing nozzles 33 extending into the burner throughthe small closed upstream end thereof.-

The power plant operates substantially as follows: Air enters the casingin at the inlet of the flow passage I2, is compressed by the compressor,and flows into a difiuser or divergent portion 35 oi the flow passage,which eflects a further compression of the air. The compressed air thenpasses through openings provided in the walls oi The compressed airmixes with the fuel atomized in the tube by the nozzles 33. The air andfuel mixture is ignited and burns steadily thereafter. The hot gases ormotive fluid comprising the products of combustion and the excess airheated by the combustion, on leaving the burner tube 3| are directed byfixed guide vanes or nozzles 38, of the turbine 2|,

into the blade passage of the turbine rotor l9.-

The turbine extracts at least sufiicient energy from the motive fluid todrive the compressor l8 and other auxiliary apparatus. The spent gasesleaving the turbine are discharged through the propulsion nozzle 23 at ahigh velocity, so that the remaining energy in the motive fluid isavailable to propel the aircraft. 4

The present invention is concerned with the lubrication system for thebearings 21, 28 and 29, and more particularly with the means for coolingthe lubricant so that it may have the desired lubricating and coolingeffects on the-bearings.

As illustrated in the drawings, the lubrication system' includes anair-lubricant cooler 40 which may be of suiflcient size to constitute areservoir, having a supply communication "-42 for flow of lubricanttherefrom to the bearings 21, 28 and 29, and a return communication 43-for flow of lubricant from the bearings to the cooler 40.

Inasmuch as the coolest air available within the power plant for coolingthe lubricant will, due to ram efi'ect, be too'hot for this purposeunder certain conditions of operation, the present invention provides aduct 46 for withdrawing a small portion of the air compressed by thecompressor I8 and directing it to a heat exchanger 41 where it passes inheat-exchange relation to cooler air supplied thereto from thecompressor inlet by the duct 48. v

On leaving the heat exchanger 41, the compressed air passes through duct49 to an air turbine 5| where it constitutes the motive fluid fordriving the turbine. In expanding through the blading 52 of the turbine5| the compressed air expands and is furthercooled to a temperaturesuitable for cooling the lubricant inthe airlubricant cooler 40, towhich it flows through the duct 53 and from which it exhausts to theatmosphere through outlet 54.

The turbine 5| is connected by shaft 56 with the impeller 51 of a blower58 which functions to promote flow of cooling air from the turbine inletthrough the duct 48, the heat exchanger 41 and discharge ducts 59 and60. Thus, the blower 58 constitutes a load on the turbine 5|, causingthe latter to remove heat energy from the air driving the air turbine.

While the invention has been shown in but one form, it will be obviousto those skilled in,

the art that it is not so limited, but is susceptible of various changesand modifications without departing from the spirit thereof.

What is claimed is:

1. In a power plant for propulsion of aircraft, an air compressorincluding a rotary element. an engine for driving said compressor andincluding a rotary element, a plurality of bearings for the rotaryelements ofv said compressor and engine, an air-lubricant cooler meansfor supplying lubricant from said air-lubricant cooler to said bearmasand for returning lubricant from said bearingsto said air-lubricantcooler, means for passing air compressed by said compressor through saidair-lubricant cooler in heat-exchange relation to lubricant therein tocool the latter, and means for cooling said compressed air prior to itspassage through said air-lubricant cooler.

2. Structure as specified in claim 1, wherein the last-mentioned meanscomprises a heat exchanger in which air uncompressed by the compressorpasses in heat exchange relation to the compressed air passing to theair-lubricant cooler to cool the latter air.

3. Structure as specified in claim 1, wherein the last-mentioned meanscomprises an expansion chamber in which the compressed air passage tothe air-lubricant cooler is expanded and thereby cooled.

4. Structure as specified in claim 1, wherein the last-mentioned meanscomprises a heatexchanger through which said compressed air is passed inheat-exchange relation to a cooling medium to reduce its temperature andmeans defining an expansion chamber in which said compressed air isfurther cooled by expansion.

5. In a power plant for propulsion of aircraft, a compressor including arotary element, a turbine for driving said compressor and including arotary element, a plurality of bearings for said rotary elements, meansproviding an inlet duct for passage of air to said compressor forcompression thereby, means providing an outlet from said compressor forair compressed thereby, a first heat exchanger, means providing acommunication between said inlet duct and said heat exchanger for flowof cooling air through the latter from the former, means providing acommunication between said outlet and said heat exchanger for flow ofcompressed air from the former through the latter in heat-exchangerelation to the cooling air, a second heat exchanger, means providing acommunication between said heat exchangers for flow of cooled'compressedair from said first heat exchanger to and through said second heatexchanger, means providing a communication between said second heatexchanger and the bearings and between said bearings and said secondheat exchanger, whereby hot lubricant from the bearings may flow to saidsecond heat exchanger and be cooled by passing therethrough inheat-transfer relation to the cool air, and cooled lubricant may flowfrom the second heat exchanger to the bearings.

- 6. In a power plant for propulsion of aircraft, a compressor includinga rotary element; an engine for driving said compressor and including arotary element; a plurality of bearings for said rotary elements; meansproviding an inlet duct fcr passage of air to said compressor forcompression thereby; means providing an outlet from said compressor forair compressed thereby; a lubrication system for said bearings andincluding a lubricant cooler, a first communication for flow flow ofheated lubricant from said bearings to said lubricant cooler; a conduitfor flow ofair from the compressor outlet to said lubricant cooler forcooling lubricant in the latter; and means interposed in said conduitfor cooling air from the compressor outlet prior to its passage throughthe lubricant cooler.

'7. Structure as specified in claim 6, wherein the last-"mentioned meanscomprises a heat exchanger and means for passing air from the compressorinlet through said heat exchanger in heatexchange relation to the airpassing from the com. pressor outlet to the lubricant cooler.

8. Structure as specified in claim 6, wherein the last-mentioned meanscomprises an air turbine motivated by the cooling air passing from thecompressor outlet to the lubricant cooler, and means for loading saidair turbine.

9. Structure as specified in claim 8, including a heat exchangerdisposed in the flow path of air from the compressor outlet to thelubricant cooler, means for passing air from the compressor inletthrough said heat exchanger in heat-exchange the lubricant cooler, endsfrom the compressor inlet said blower bein the air REFERENCES CITED Theiollowing references are of record in the tile of this patent:

UNITED STATES PATENTS Name Date Weller Feb. 1'7, 1948 OTHER REFERENCESFig. 2 of article entitled Air Conditioning Turbine-Propelled Aircraft,Aviation, for February 1947, pages 49 to 52 inclusive.

Number Certificate of Correction Patent No. 2,487,842 November 15, 1949'IRVIN WHITEMAN ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 4, line 24, for the word passage read passing;

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 7th day of March, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

